Isopropyl-aryl compounds chlorinated in the isopropyl radical and process of making same



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2,693,494 l lacgslglgf lnfavlvdlagbgnagganed, for Tetrachloracetones and ISOPROPYL-ARYL COMPOUNDS CHLORINATED IN THE ISOPROPYL RADICAL AND PROCESS OF MAKING SAME Max Geiger and Eduard Usteri, Basel, and Charles N Drawing. Application December 11, 1947, Serial No. 791,172

Claims priority, application Switzerland December 18, 1946 9 Claims. (Cl. 260-651) The manufacture of isopropyl-aryl compounds chlorinated in the isopropyl radical has been attempted hitherto by two methods, namely either'the direct chlorination of the side chain, that is to say the isopropyl radical, or the combination of dichloracetones with aromatic hydrocarbons by means of aluminum chloride. However, the first method does not lead to homogeneous products, but to mixtures of isomeric bodies chlorinated to different degrees, which cannot be separated. By the second method only resinous bodies are obtained.

According to the present invention isopropyl-aryl compounds chlorinated in the isopropyl radical are made in a simple manner by condensing an aromatic compound consisting of at most two condensed siX-membered nuclei which are free from substituents which contain easily replaceable atoms, form salts, and have a predominantly meta-directing effect, in the presence of aluminum chloride, with a chlorinated acetone corresponding to the general formula wherein at least one X and at most two Xs represent chlorine atoms and the remaining Xs represent hydrogen atoms.

As aromatic compounds there may be used compounds consisting of at most two condensed six-membered nuclei which are free from substituents which contain easily replaceable atoms, form salts and have a predominantly meta-directing effect. Thus, there are excluded substituted, aromatic compounds of the benzeneand naphthalene series which contain substituents with easily replaceable atoms, such as CPl -halogen-groups, or substituents which form salts, such as OH-, NH2-, NH-acyl- N(alkyl) -groups, or substituents which have a predominantly meta-directing effect, such as NO COOH-, CN-, CCl CO-, SO I-I- or 'SCN-groups. Thus, as compounds suitable as starting materials for the present process there may be used unsubstituted aromatic hydrocarbons free from alkyl groups, such as, for example, benzene or naphthalene; further there may be used aromatic hydrocarbons substituted by one or more alkyl groups, alkoxy groups or halogen atoms, such as, for example, toluene, ethylbenzene, xylenes, tertiary-butylbenzene, anisole, chlorobenzene, ortho dichlorobenzene, 2:4 dichlorotoluene, alpha-chloronaphthalene and the like. Among these compounds toluene, ortho-xylene, anisole, naphthalene and alpha-chloronaphthalene are easily condensable, whereas benzene, ethyl-benzene, tertiary-butylbenzene, chlorobenzene, ortho-dichlorobenzene and 2:4-dichlorotoluene are less reactive and therefore more diificult to condense.

The chlorinated acetones used for the condensation,

which correspond to the general formula given above,;

are 1:1:3-trichloracetone, 1:1:323- and 1:1:1:3-tetracbloracetone, and also mixtures of such chlorinated acetones, especially mixtures of the symmetrical and asymmetrical tetrachloracetone such as are obtained by the 30 process of application Ser. No. 791,171 filed December The condensation is conducted at low temperature and in presence of aluminum chloride. The temperature to be maintained depends on the reactivity of the aromatic compounds used; in the case of easily condensable aromatic compounds it is advantageous to maintain a temperature of, for example, 15 C. to 10 C., and in the case of those more diflicult to condense a temperature of 5 C. to +5 C.

The condensation products so obtained correspond to the general formula wherein at least one Z and at most two Zs represent an aromatic radical consisting of at most two condensed six-membered nuclei free from substituents which contain easily replaceable atoms, form salts and have a predominantly meta-directing eifect, and the remaining Z stands for a chlorine atom, and wherein at least one X and at most two Xs represent chlorine atoms and the remaining Xs represent hydrogen atoms.

When easily condensable unsubstituted or substituted aromatic hydrocarbons are used, for example, toluene, orthoxylene, naphthalene, anisole or u-chloronaphthalene, it is possible, depending on the reaction conditions, to obtain products of the above general formula in which each Z represents an aromatic radical and X has the meaning given above.

When unsubstituted or substituted aromatic hydrocarbons diflicult to condense are used, for example, benzene, ethyl-benzene, tertiary butyl-benzene, chlorobenzene ortho-dichlorobenzene or 2:4-dichlorotoluene, there are usually obtained products which correspond to the general formula in which Z and X have the meanings given above.

The condensation products obtained as described above are either crystalline compounds or viscous oils, which can be used as intermediate products for a very wide variety of purposes and also for the production of agents for combating pests, or which themselves find application as agents for combating pests.

The possibility of carrying out the present process could not be foreseen, because, as stated above, the condensation of aromatic hydrocarbons with dichloracetones and aluminum chloride leads to resinous products. It is also very surprising that only certain chlorinated acetones are capable of combining.

The following examples illustrate the invention, the parts being by weight: I

Example 1 CHClz boils at 120-122" C. under a pressure of 0.22 mm., and is a colorless, almost odorless oil.

Example 2 230 parts of 1:1:3:3-tetrachloracetone and 86 parts of chlorobenzene are mixed-in the course of 3 hours with 100 parts of aluminum chloride at C. to 2 C. while stirring Well. The reaction mixture is then further stirred for hours longer in an ice bath. The dark viscous mass is then poured on to ice, taken up in ether, and washed neutral. After drying the ethereal solution and evaporating the ether the excess of tetrachloracetone is distilled at about 70 C. under a pressure of 12- mm., and then the symmetrical pentachlorisopropyl-para-chlorobenzene corresponding to the formula CHCla OHClr is obtained in the form of a colorless oil which boils at 130 C. under a pressure of 0.05 mm. and solidifies in crystalline form. It melts at 50-52 C. The yield amounts to 70-80 per cent. calculated on the tetrachloracetone which undergoes reaction.

By treatment with 1 mol of caustic soda in alcoholic solution 1 mol of hydrochloric acid can be split off from the symmetrical pentachlorisopropyl-para-chlorobenzene so obtained to form tetrachlorisopropenyl-para-chlorobenzene, which is stable to further treatment with the caustic soda solution.

In an analogous manner there are obtained from symmetrical tetrachloracetone and benzene, ethylbenzene, tertiary-butyl-benzene or ortho-dichlorobenzene the corresponding condensation products, namely,-pentachlorisopropyl-benzene boiling at 173-176 C. under 15 mm. pressure, pentachlorisopropyl-ethylbenzene boiling at 133 C. under 0.03 mm. pressure, pentachlorisopropyltertiary-butylbenzene melting at 102 C., and pentachlorisopropyl-ortho-dichlorobenzene'boiling at 153-154 C. under 0.1 mm. pressure.

Example 3 11 parts of aluminum chloride are introduced in the course of 2 hours, while stirring well and cooling with ice, into a mixture of 16 parts of 121:1:3-tetrachloracetone and 18 parts of chlorobenzene. The whole is then stirred at 0-2 C. for a further 22 hours, the dark viscous reaction product is decomposed with ice, taken up in ether, Washed neutral with Water, and filtered to remove insoluble White flocks. By distillation a small quantity of chlorobenzene and tetrachloracetone is recovered from the crude product. The asymmetrical penta-chlorisopropylwpara-chlorobenzene corresponding to the formula Gaga...

OHiCl boils at 143-145" C. under a pressure of 0.05 mm. and, after recrystallization, melts at 9091 C.

In the same manner ,a mixture of 1:1:323- and 111:3- tetrachloracetone may be used, whereby a mixture of the isomeric pentachlorisopropyl-para-chlorobenzenes is obtained.

Example 4 70 parts of benzene and 15 parts of a mixture of symmetrical and asymmetrical tetrachloracetone are mixed in the course of 3 hours with 10 parts of aluminum chloride, while stirring at 0-5 C. The whole is then further stirred in an ice bath for 20 hours.

The dark reaction mass is poured onto ice and the oily layer taken up in benzene. The benzene solution is washed with water until neutral and dried, whereupon the solvent is distilled off. The mixture of the isomeric pentachlorisopropyl benzenes is rectified in a vacuum. It boils at 173-176 C. under a pressure of 15 mm. mercury.

Example 5 4.5 parts of aluminum chloride are introduced in the course of one hour at -10 C. to -l5 C., while stirring, into a mixture of 50 parts of toluene and 20 parts of 1:1:3:3-tetrachloracetone. The mixture becomes dark in color. After stirring for 4 hours at 10 C. to -l5 C. the reaction mass is decomposed with acidified icewater, and extracted with a solvent, for example, toluene. After drying, the solvent is distilled. The residue is fractionated under greatly reduced pressure. After being distilled twice the resulting pentachlorisopropyl-toluene boils at 114-116 C. under a pressure of 0.02 mm. in the form of a colorless viscous oil.

In the same manner a mixture of 111:3:3- and l:1:1:3- tetrachloracetone may be used, whereby a mixture of the isomeric pentachlorisopropyl-toluenes is obtained.

Example 6 4.5 parts of aluminum chloride are introduced at 10 C. to -15 C. in the course of one hour, while stirring into a mixture of 50 parts of anisole and 20 parts of 1:1:3:3-tetrachloracetone. After stirring for 7 hours at l0 C. to -15 C. the dark reaction mass is decomposed with acidified ice-water, the oily layer is washed with water and dried. The excess of anisole and unreactecl tetrachloracetone are then removed by distillation under reduced pressure, and the residue is fractionated under greatly reduced pressure. The resulting pentachlorisopropyl-anisole boils at 161-165 C. under a pressure of 0.03 mm. and melts, after recrystallisation from petroleum ether, at -102 C.

Example 7 13 parts of aluminum chloride are introduced in the course of 2 hours at 0C. to 5 C., While stirring, into a mixture of 100 parts of anisole and 20 parts of 1:1:3 :3- tetrachloracetone. The dark mixture is stirred for 20 hours at the same temperature, and then decomposed with ice and dilute hydrochloric acid. The oily layer is separated, washed with water, dried, and the excess of anisole is distilled under reduced pressure. The distillation residue solidifies in crystalline form. It is purified by recrystallisation from a mixture of chloroform and methanol. The bis-dichloromethyl-bis-anisyl-methane so obtained melts at 148-149 C.

Example 8 4.5 parts of aluminum chloride are introduced in the course of one hour at 10.C. to 15 C., while stirring, into amixture of 60 parts of a-chloronaphthalene and 20 parts of 1:1:3:3-tetrachloracetone. After stirring at -10 C. to l5 C. for 6 hours, the reaction mass is decomposed with acidified ice-water, and the oily layer is separated, washed with water and dried. The excess of a-chloro-naphthalene is then distilled under reduced pressure, and the residue is fractionated under greatly reduced pressure. After the second distillation, 'the resulting pentachlorisopropyl-a-chloronaphthalene boils at l85187 C. ,under a'pressure of 0.02 mm. in the form of a very viscous oil.

Having thus described the invention, what is claimed 1. A mixture of compounds of the general formulae wherein at least one Z and at mosttwo Zs represent a radical selected from the group consisting of phenyl, naphthyl and the corresponding alkyl-, -alkoxyand halogen-substituted radicals, and the remaining Z stands for a chlorine atom.

2. A mixture of compounds of the general formulae 4. A mixture of the pentachlorisopropyl-toluenes of 5. A mixture of the pentachlorisopropyl-parachlorobenzenes of the formulae 6. A process for the manufacture of an isopropylaryl compound, chlorinated in the isopropyl radical, by condensing, at a temperature of 15 C. to +5 C., an aromatic compound selected from the group consisting of benzene, naphthalene and their alkyl, alkoxy and halogen derivatives, which aromatic compound contains at least one hydrogen atom linked to a nuclear carbon atom, With a mixture of symmetrical and asymmetrical tetrachloracetone, in the presence of, as further reactant, about %-1 mol of aluminum chloride for each mol of the mixture of symmetrical and asymmetrical tetrachloracetone.

7. A process for the manufacture of a mixture of the penta-chlorisopropyl benzenes by condensing benzene at a temperature of 15 C. to +5 C. with a mixture of symmetrical and asymmetrical tetrachloracetone in the presence of, as further reactant, about /a1 mol of aluminum chloride for each mol of mixture of symmetrical and asymmetrical tetrachloracetone.

8. A process for the manufacture of a mixture of the penta-chlorisopropyl toluenes by condensing toluene at a temperature of -15 C. to +5 C. with a mixture of symmetrical and asymmetrical tetrachloracetone in the presence of, as further reactant, about /a--1 mol of aluminum chloride for each mol of mixture of symmetrical and asymmetrical tetrachloracetone.

9. A process for the manufacture of a mixture of the penta-chlorisopropyl para-chlorobenzenes by condensing chlorobenzene at a temperature of l5 C. to +5 C. with a mixture of symmetrical and asymmetrical tetrachloracetone in the presence of, as further reactant, about /=,--l mol of aluminum chloride for each mol of mixture of symmetrical and asymmetrical tetrachloracetone.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,961,397 Schoeller et al June 5, 1934 2,430,822 Nevison Nov. 11, 1947 2,455,643 Bakalar Dec. 7, 1948 

1. A MICTURE OF COMPOUNDS OF THE GENERAL FORMULAE
 6. A PROCESS FOR THE MANUFACTURE OF AN ISOPROPYLARYL COMPOUND, CHLORINATED IN THE ISOPROPYL RADICAL, BY CONDENSING, AT A TEMPERATURE OF -15* C. TO + 5* C., AN AROMATIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF BENZENE, NAPHTHALENE AND THEIR ALKYL, ALKOXY AND HALOGEN DERIVATIVES, WHICH AROMATIC COMPOUND CONTAINS AT LEAST ONE HYDROGEN ATOM LINKED TO A NUCLEAR CARBON ATOM, WITH A MIXTURE OF SYMMETRICAL AND ASYMMETRICAL TETRACHLORACETONE, IN THE PRESENCE OF, AS FURTHER REACTANT, ABOUT 1/3-1 MOL OF ALUMINU CHLORIDE FOR EACH MOL OF THE MIXTURE OF SYMMETRICAL AND ASYMMETRICAL TETRACHLORACETONE. 